DE2424371C2 - Process for the production of sulfamic acids - Google Patents

Description

Il

R — N — C-N — R (TJ)

I I

H H

wherein R has the aforementioned meaning, with 100 percent by weight sulfur trioxide in an amount of 1 to 13 mol. ie moles of starting material II. in an inert organic solvent at -20 to 140 ⁰ C and

b) the reaction mixture formed by 96 to 100 percent strength by weight sulfuric acid in an amount of 1 to 1.5 moles, per MoI starting material II, at 20 to 140 ⁰ C, in each case under atmospheric or superatmospheric pressure, is reacted.

It is known from Houben-Weyl, Methods of Organic Chemistry, Volume 11/2, pages 654 and 655 that Ν, Ν'-Dialkylureas first sulfonated by the action of oleum and then split to amidosulfonic acids will. As shown by the example of methylsulfamic acid, there are no other than oleum Sulfonierungsmiuel and further no organic solvents used in the reaction. The German Patent 6 36 329 shows the same reaction and mentions an aftertreatment with sulfuric acid or water, without further describing these embodiments. A work in the Journal of the American Chemical Society, Volume 75, page 1408 (1953) also shows the reaction described by Houben-Weyl with Oleum without further treatment; the difficulty in responding is specifically noted to achieve an optimum yield and in particular to suppress the formation of Aikylammoniumsulfat or decrease. The time at which the starting materials are added and the temperature control of the reaction play a role a significant role. When working up, the end product has to be washed several times with ether but in spite of these purification operations it is still sulphate and can only be achieved by dissolving in methanol and precipitation Adding larger amounts of ether can be cleaned.

British patent specification 11 85 439 points out the disadvantage of using sulfuric acid, also in the form of oleum, since when sulfuric acid is used a highly contaminated end product is always obtained and the removal of the sulfuric acid is cumbersome and difficult. Therefore recommends a Arbeitswei ^c e, in the substituted urea with at least double the equimolar amounts of sulfur trioxide in the presence of an organic solvent is reacted. It is emphasized that usually 2 to 4, preferably 3, moles of sulfur trioxide are used per mole of urea. The reaction can also be carried out in two stages, with sulfur trioxide having to be added to the reaction mixture in each stage. US Pat. No. 3,555,081 describes the same procedure in the synthesis of N-cyclohexyiamidosulfonic acid and

thus also shows that the use of sulfuric acid leads to contaminated end products. According to their teaching (Column 3, lines 45 to 54) it is crucial that no sulfuric acid is present in the reaction mixture. at two-stage working methods, sulfuric acid may only be used together with sulfur trioxide in the form of oleum in the second reaction step can be used.

The German Offenlegungsschrift 21 64 197 describes the preparation of sulfamic acids by reacting isocyanates with oleum at at least 25 ° C. in organic solvents. A process is also known (DE-OS 16 68 106) for producing alkali and alkaline earth salts of cyclohexylamido sulfonic acid by reacting ammonium amido sulfonate or ammonium imidodisulfonate with cyclohexylamine in the presence of a non-aromatic secondary amine and subsequent hydrolysis. In all examples, the reaction is carried out at a temperature between 150 and 180 ^{° C.}

The German Offenlegungsschrift 16 43 837 describes a preparation of cyclohexylsulfamic acid by Reaction of nitrocyclohexane with sodium dithionite in an aqueous reaction medium. Like the example shows, you put the starting materials in a dispersion of water and organic solvent, which in the end separated by decanting one of the 2 layers. Yields are not given.

From the German Offenlegungsschrift 16 43 838 is known. Cyclohexylsulfamic acid by reacting Nitrocyclohexane and sulfur dioxide in an aqueous medium in the presence of zinc, tin or iron in one Establish pH below 3.3.

The German Offenlegungsschrift 15 68 772 describes a process for the production of N-substituted Sulphamate by reacting sulfur trioxide and primary or secondary amines in the vapor state

130 to 200 ^° C. The two starting materials are fed separately in the vapor state through nozzles to a mixing zone of a reaction vessel (Example 1). The air in the zone is swirled by a fan; the reaction temperature in the zone is 170 to 180 ^° C. (examples). In the case of a cyclohexylamine conversion, mixtures of cyclohexylammonium-N-cyclohexylsulfamate, N.N'-dicyclohexylsulfamide and cyclohexylammonium sulfate are obtained. The yield of N-cyclohexylsulfamate in the examples is from 45 to 80%.

The invention now relates to the method shown in the preceding claim for the production of Amido sulfonic acids.

The reaction can be carried out by the following formulas in the case of using Ν, Ν'-dimethylurea be reproduced:

O O

H ₃ C-NH-C-NH-CH ₃ + SO ₃

H ₃ C-NH-CN-CH ₃ SO ₃ H

+ H ₂ SO ₄

2H ₃ C-NH-SO ₃ HS-CO ₂

Compared to the known method, the method according to the invention provides on a simpler and more economical way amidosulfonic acids in better yield and purity. It becomes one bath in two Stages carried out; it is a characteristic feature of the invention that in the second stage sulfur trioxide is not supplied and sulfur trioxide is used in smaller amounts in the first stage.

With regard to DE-OS 21 64197 and DE-OS 16 43 838, higher yields of end product are obtained in better purity, with regard to DE-OS 16 43 837 and DE-OS 15 68 772 is the procedure and work-up of the end product easier and more economical. The production of dispersions of the organic raw material in water and the separation of the 2-phases of the reaction mixture are avoided. Also are sulfuric acid and its anhydride is more economical and more accessible compared to sodium dithionite. One use of finely divided metal is avoided. With regard to DE-OS 16 68 106 can be much deeper Temperatures are used and the addition of secondary amines can be saved. With regard to this Offenlegungsschrift is also the easier accessibility and the economy of the invention Starting material urea advantageously /. With reference to the method described in DE-OS 15 68 772 are Work-up, yield and purity of the end product as well as simpler and more economical working method advantages of the method according to the invention.

All these advantageous results of the method according to the invention are in view of the prior art Technology surprising.

Preferred starting materials II and correspondingly preferred end materials I are those in whose formulas R an alkyl radical with 1 to 12, preferably 1 to 5 carbon atoms, a cyclohexyl radical, an aralkyl radical with 7 to 12 carbon atoms, or a phenyl radical. The aforementioned residues can still go through under groups which are inert to the reaction conditions, e.g. B. alkyl groups having 1 to 4 carbon atoms, may be substituted.

Examples of the following ureas are suitable as starting materials II: N.N'-dimethylurea, N ₁ N'-, diisopropylurea, N, N'-di-n-butylurea, Ν, Ν'-diodecylurea, Ν, Ν'-di-sec .-butylurea, N, N'-di-tert-butylurea, N, N'-diethylurea, N.N'-dicyclohexylurea, Ν, Ν'-dibenzylurea, N, N'-diphenylurea, N, N'-di -p-tolylurea, N, N'-pi- (p-ethylphenyi) -urea, N, N'-di- (p-xylyl) -urea.

The reaction is carried out in the first step with 1 to 1.9, preferably 1 to 1.5 mol of sulfur trioxide and in the second Step carried out with 1 to 1.5, preferably 1 to 1.2 moles of sulfuric acid per mole of starting material II. sulfuric acid is usually used in the form of sulfuric acid (100%) (monohydrate); if necessary comes 96 to 100 percent by weight water-containing sulfuric acid is also possible. Sulfur trioxide can be in solid form or expediently be used in liquid form or as a gas; 100 percent is advantageous Sulfur trioxide in question, if appropriate it can also be diluted with an inert gas such as carbon dioxide. One can but also substances that release sulfur trioxide under the reaction conditions, for example Addition compounds of sulfur trioxide, e.g. B. with ethers such as tetrahydrofuran, di-C ^ -chlorathylJ-ether, 1,4-dioxane; Ν, Ν-disubstituted carboxamides, such as Ν, Ν-dimethylformamide; with tertiary amines, e.g. B. Pyridine, triethylamine, trimethylamine, tributylamine, quinoline, quinaldine, dimethylaniline, triphenylamine, N-methylmorpholine, N-ethylmorpholine, N-methylpiperidine, N-ethylimidazole, N-methylethyleneimine, N-ethylpentamethyleneimine; or addition compounds of chlorosulfonic acid with the aforementioned amines, in particular Pyridine; or corresponding mixtures. Substances that contain sulfuric acid, e.g. B. Oleum, do not take place of sulfur trioxide into consideration. Regarding the definition of 100 percent sulfur trioxide, see UIlmanns Encyklopadie der technischen Chemie, Volume 15, pages 465-467 and regarding the preparation of Addition compounds on Houben-Weyl (loc. Cit.), Volume VI / 2, pages 455 to 457 and Volume IX, pages 503 to 508, referenced.

The reaction is generally carried out at a temperature of -20 ° C to + 14O ⁰ C, in the first step advantageously from 0 to 80, preferably from 15 to 60, in the second step suitably from +20 ⁰ C to + 140 ⁰ C, preferably carried out at from 40 to 100 ^° C., without pressure or under pressure, continuously or discontinuously. Organic solvents which are inert under the reaction conditions are used in both steps, with

If advantageously the total amount of organic solvent has already been added to the first reaction step

Ü will. As a solvent, for. B. in question: aromatic hydrocarbons, e.g. B. toluene, ethylbenzene, o-,

§ m-, p-xyloI, isopropylbenzoL methylnaphthalene; Halogenated hydrocarbons, especially chlorinated hydrocarbons

I fabrics, e.g. B. tetrachlorethylene, allyl chloride, cyclohexyl chloride, dichloropropane, methylene chloride, dichlorobutane,

I 5 isopropyl bromide, n-propyl bromide, batyl bromide, chloroform, ethyl iodide, propyl iodide, chloronaphthalene, dichloro- % naphthalene. Carbon tetrachloride, tetrachloroethane, trichloroethane, trichlorethylene, pentachloroethane, trichloroethane

I fluoromethane, cis-dichloroethylene, o-, m-, p-difluorobenzene, 1,2-di-chloroethane, 1,1-dichloroethane, n-propyl chloride,

I 1,2-cis-dichloroathylene, n-butyl chloride, 2-, 3- and iso-butyl chloride, chlorobenzene, fluorobenzene, bromobenzene, iodine

f, benzene, o-, p- and m-diclorobenzene, o-, p-, m-dibromobenzene, o-, m-, p-chlorotoluene, 1 ^ -trichlorobenzene, 1,10-di-

ij ίο bromdekaii, 1,4-dibromobutane; and corresponding mixtures. The solvent is expediently used in I an amount from 400 to 10,000% by weight, preferably from 400 to 1000% by weight, based on starting material I.

% The reaction can be carried out as follows: A mixture of starting material II, solvent and

'} Sulfur trioxide is kept at the reaction temperature for 2 to 6 hours. The

'Urea II is first suspended in a solvent and 100-gel in the mixture with thorough mixing

ΐ Weight percent sulfur trioxide has been entered. Then sulfuric acid is added and the mixture in the two i th reaction step for 1 to 6 hours at the reaction temperature, which is advantageously higher than that of

ν first reaction step is held. Now the end product is made from the reaction mixture in the usual way,

T ₁ z. B. by filtration, separated. In an advantageous embodiment, oleum is entwined. to which one

f removes free sulfur trioxide by heating and passes it into the first reaction step and then the remaining one

20 100 percent by weight sulfuric acid fed to the second reaction step.

The obtainable by the process of the invention are compounds of sweeteners, in particular the CYCLOHEPTA ^v exylarnidGSuifonsäure or their calcium, sodium and potassium salts, and valuable starting materials for the

Manufacture of sweeteners, colors and pesticides. For example, through Chlorination, e.g. B. with thionyl chloride, the corresponding sulfonic acid chlorides, e.g. B. Isopropylaminosulfonylchlo-25 rid, be prepared; from them you can by reaction with anthranilic acid or its salts in the German patent 21 04 682 produce o-SuIfamidobenzoic acids described. By cyclizing these Substances, e.g. B. by the method described in German Patent 21 05 687, one arrives at the 2,13-Benzothiadiazin-4-one-2 ^ -dioxiden, their use for pesticides and pharmaceuticals in the same patent. Regarding the use, reference is made to the aforementioned publications gene and to DE-AS 11 20 456, DE-PS 12 42 627 and DE-OS 15 42 836 referenced.

The parts listed in the following examples are parts by weight. They relate to the volume parts like kilograms to liters.

example 1

88 parts of Ν, Ν'-dimethylurea are slurried in 250 parts by volume of dichloroethane. 96 parts of gaseous SO ₃ (100% by weight) are introduced into the mixture at 25 ° C. A clear solution is formed. The mixture is then heated to reflux (70 to 75 ° C.) and 98 parts of H ₂ SO ₄ (100% by weight) are added. Crystals precipitate under ^ development. After cooling, the mixture is filtered off with suction and washed with 250 parts of dichloroethane 40.

Yield: 222 parts (practically quantitative) methylamido sulfonic acid with a melting point of 182.3 ° C.

Example 2

45 144 parts of Ν, Ν'-diisopropylurea are suspended in 250 parts by volume of dichloroethane. At 25 ° C., 104 parts of SO ₃ (100% by weight) are added over the course of one hour. The suspension turns into a clear solution. When the addition is complete, the mixture is heated to reflux temperature (70 to 75 ° C.), and 98 parts of 100 percent sulfuric acid are then added. Isopropylamidosulfonic acid precipitates in crystalline form with evolution of CO2. After cooling and filtering off, 268 parts are obtained (practically

50 quantitative) isopropylamidosulfonic acid with a melting point of 167 ° C.

Example 3

224 parts of N, N'-dicyclohexylurea are slurried in 2000 parts by volume of 1 ^ -dichloroethane. 304 parts of SO ₃ (100% by weight) are added in 60 minutes. A clear solution is created. After heating to reflux, 98 parts of sulfuric acid (100% by weight) are added. The cyclohexylaminosulfonic acid precipitates with evolution of _{CO 2.}

Yield: 345 parts (96.4% of theory) of cyclohexylaminosulfonic acid with a melting point of 168 ° C.

Claims (1)

Claim: Process for the preparation of sulfamic acids of the formula
R — N — SO ₃ HO) wherein R is an aliphatic, cycloaliphatic ^ araliphatic or aromatic radical, through ίο implementation of ureas with sulfur trioxide, characterized in that one a) substituted ureas of the formula